[Xen-devel] [PATCH v2] fix potential int overflow in efi/boot

[Stefano Stabellini <stefano@xxxxxxxxxxx>]

HorizontalResolution and VerticalResolution are 32bit, while size is
64bit. As it stands multiplications are evaluated with 32bit arithmetic,
which could overflow. Cast HorizontalResolution to 64bit to avoid that.

Coverity-ID: 1381858

Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

---
Changes in v2:
- remove stray space
- fix other multiplication

diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 56544dc..3e5e4ab 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -684,10 +684,10 @@ static UINTN __init 
efi_find_gop_mode(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop,
             break;
         }
         if ( !cols && !rows &&
-             mode_info->HorizontalResolution *
+             (UINTN)mode_info->HorizontalResolution *
              mode_info->VerticalResolution > size )
         {
-            size = mode_info->HorizontalResolution *
+            size = (UINTN)mode_info->HorizontalResolution *
                    mode_info->VerticalResolution;
             gop_mode = i;
         }

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